Metallic feedstock such as slabs, hot strip or cold strip, sheet metal, tubes etc. made from material such as iron, steel, non-ferrous metals or other metallic materials are subjected on a large industrial scale to various stages of processing and refinement. Typical processing stages are the rolling out of cast slabs into hot strip or the rolling down of the hot strip to the thickness desired by the customer in a cold rolling mill train, for example a tandem mill train.
Conventionally rolling mills occur as separate systems which receive their rolling stock for example from a separate continuous casting system. In modern combined casting and rolling stations hot strip can be manufactured in a continuous process, especially as an endless strip. A combined casting and rolling station is disclosed for example in WO 96/01710 or in DE 694 08 595 T2.
The decisive component for processing rolling stock is a rolling stand, with which for example slabs can be rolled into a strip in consecutive rolling passes. Rolling stands are used in practically all rolling mill trains, especially in hot strip rolling trains and cold strip rolling trains.
After the hot rolling the strips can be subjected to further processing steps. At the end of the rolling train the rolled-down strip is usually rolled up into coils with the aid of a coiler. As an alternative there is a direct coupling to a cold rolling station and/or processing line in the continuous process.
The hot strip can be subjected to further intermediate steps, such as heat treatment for example, before it is conveyed to a cold rolling mill train. At the end of a cold rolling mill train there is usually a winding coiler for receiving the rolled strip combined with shears if necessary in the continuous process.
During rolling high torques must be applied for processing the rolling stock. For this reason powerful electric motors are used to drive the rolls, the torque of which is frequently further increased with the aid of a reduction gear. DE 199 11 751 C1 describes a drive device for a rolling stand. Powerful electric motors as well as suitable transmissions are very heavy and voluminous.
The electric motors complete with gearing must—relative to the processing direction of the rolling stock—be arranged to the side, which means that they significantly increase the area to be occupied by a fabrication shop. As an alternative to this JP 10-235416 proposes integrating a compact superconducting electric motor into the inside of a roll of a rolling stand. Such an embodiment results in mechanical problems since the roll concerned, with its stability thus reduced, will suffer deformations with high rolling forces.